It is possible that you do have another type growing with your black, but I think that you would have seen some growth before now, as it would have died without some part of the plant being above ground level.

My black, and a few other phyllostachys of mine, sometimes put up 'thin' shoots that will also have thinner than normal leaves. Usually caused by stress in growing conditions, either a lack of water for a long period of time before shooting, or perhaps a lack of growing space as is the case when grown in a pot.

Kt

THe "different leaves" is the rhizone.
It hit the side of your pot and grew up.
You have to plant your black boo in a REALLY big pot, such as a half barrel, and even that will keep it happy for about 2-3 years.
Black bamboo isn't the best species to pot grow.
I know, I tried it.
So, next spring, buy a half barrel and replant it.
Then, watch your boo grow! It certainly will!
GOod Luck!
Oh, by the way, if all of it's leaves fall off in early spring, like April, that is normal. They grow back fast.

well the pot I have it in is already pretty large barrel, and all the new clums are comming up in the middle, not on the sides. So I'm going to plant it in the ground next spring. thanks for all the help.

If you're in USDA 4 it won't be hardy outside. But maybe you are saying you are in Sunset 4.

if u cut bamboo leaves, will they grow back, or continue to turn brown at the ends